Adsorber for humidity and odorous gas exchange

ABSTRACT

In an adsorbing body for humidity and odorous gas exchange such as an adsorbing sheet for dehumidification, an adsorbing element for dehumidification or an adsorbing element for total heat energy exchange, a sheet or a honeycomb laminate is impregnated or coated with silica sol containing, as solid content, not more than 30% of the silica sol weight of minute silica particles not larger than 120 Å in diameter which contain many stable silanol radicals on the surface and 0.01-1% of alkali metal ion Na 2 O. It is then dried to rigidly fix silica gel. Other humidity adsorbing or absorbing agents such as zeolite, organic high-polymer electrolyte, etc. may be mixed in said silica sol. Silica gel with excellent humidity adsorbing ability can be strongly adhered to a sheet or a honeycomb laminate in an extremely simple method.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The present invention relates to an adsorber for humidity and odorousgas exchange such as an adsorbing sheet for dehumidification and to ahoneycomb adsorbing element for humidity and odorous gas exchange suchas an adsorbing element for dehumidification or an adsorbing element forhumidity and sensible heat exchange (called a humidity exchanging bodyhereinafter).

b. Description of the Prior Art

A honeycomb element using inorganic humidity adsorbing agents such asmolecular sieves like zeolite, silica gel and lithium chloride fordehumidification or total heat (humidity and sensible heat) energyexchange, has been used. And the present applicants manufacture and sellhumidity and odorous gas exchangers in which silica gel or metalsilicate gel is synthesized by chemical reaction of acid or aqueoussolution of metallic salt after impregnating a laminate with water glasswhich is then rigidly adhered (Japanese Pat. No. 1,542,374 and the U.S.Pat. No. 4,911,775). These adsorbers for dehumidification are used forremoving humidity from gases such as air and nitrogen gas in variousfields such as semiconductor industry, film industry, food industry andarmy. A honeycomb element for total heat energy exchange is used as atotal heat energy exchanger for buildings, factories and houses forexchanging humidity and sensible heat simultaneously.

SUMMARY OF THE INVENTION

The prior adsorbents such as molecular sieves like zeolite and silicagel mentioned above are dispersed in binders such as silica sol andalumina sol. A honeycomb element is soaked in this dispersion toimpregnate minute particles of the inorganic humidity adsorbing agentsmentioned above in the sheet that forms the honeycomb element and to fixthem rigidly in the sheet. Or in another prior method, minute particlesof inorganic humidity adsorbing agents are fixed rigidly by usingbinders to the sheet that forms the honeycomb element, which sheet isthen laminated and shaped in honeycomb structure. In such methods,binders decrease adsorbing area of adsorbents, lowering their adsorbingability rather than contribute to humidity adsorption. The presentinvention is to obtain a high efficiency humidity adsorbing sheet and ahoneycomb element for humidity and odorous gas exchange by a method assimple as to impregnate one kind of particular silica sol, thus solidifyby gelatinize, without using minute particles of such inorganic humidityadsorbing agents nor binders for binding these agents.

The present invention is to obtain a humidity exchanging body by usingsilica sol which contains silica particles of diameter not larger thanapproximately 120 Å, having numerous stable silanol radicals on thesurface, or by adding various other adsorbents are added to the silicasol, impregnating or coating the mixture to a sheet or to a laminatewith numerous small channels (called a honeycomb laminate hereinafter),and by drying it to gelatinize and to fix rigidly minute particles ofsilica in fiber gaps of and on the surface of the sheet in the laminate.

The silica sol used here contains as solid content not more than 30% ofminute particles of silica of diameter not larger than approximately 120Å having numerous silanol radicals on the surface. When this sol isgelatinized by drying by means of heating or others, minute particles ofsilica are bound in porous structure, binding to one another, to formmicropores. These micropores, with numerous silanol radicals on thesurface of minute particles of silica, exhibit strong moisture adsorbingability. When the diameter of particles in silica sol is big, thediameter of micropores formed by linking of the particle becomes toobig, so their moisture adsorbing effect is decreased and linking forceof the particles is weakened. Therefore it is unsuitable to be used as ahoneycomb humidity adsorbing body. On the other hand very small amountof alkali metal ion contained in silica sol also contributes to moistureadsorbing ability. Therefore used is sol into which a comparativelylarge amount of this, too, is mixed. Examples are explained below indetail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a honeycomb block;

FIG. 2 is a sectional view of a single-faced corrugated sheet;

FIG. 3 is an explanatory illustration of a device for measuring theamount of humidity adsorbed by an adsorbing sheet for humidity andodorous gas exchange against time lapse;

FIG. 4 is a graph showing the humidity adsorption quantity by theadsorbing sheet for humidity and odorous gas exchange of the presentinvention against time lapse;

FIG. 5 is a graph showing heat exchange efficiency of a cross-flow typetotal heat energy exchange element;

FIG. 6 is a graph showing heat exchange efficiency of a cross-flow typetotal heat energy exchange element;

FIG. 7 is a sectional view of a single-faced corrugated sheet;

FIG. 8 is a perspective view of a total heat energy exchange rotor;

FIG. 9 is a graph showing total heat energy exchange efficiency of thetotal heat energy exchange rotor of the present invention and of theprior one in winter conditions;

FIG. 10 is a sectional view of a single-faced corrugated sheet;

FIG. 11 is a perspective view of a honeycomb rotor for dehumidification;

FIG. 12 is a partial cutaway perspective view of a dehumidifier;

FIG. 13 is a graph showing dehumidifying efficiency of a honeycomb rotorfor dehumidification;

FIG. 14 is a central vertical sectional view of a rotary total heatenergy exchanger;

FIG. 15 is a graph showing relation between sodium ion content in silicasol and adsorption speed; and

FIG. 16 is a constitutional formula of Diaion SK1B, a strong acid cationexchange resin sodium type (neutral).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

TABLE 1 Example No. 1 Silica Sol Silica Particle Silica Solid ContentNa₂O Content in Sample Diameter (Å) in Sol (%) Silica Sol (%) No. 1 40 8— 2 70 20 0.3 3 150 20 0.1 4 250 48 0.2 5 450 20 0.2

Ceramic fiber paper of 0.2 mm thickness, preferably after it is baked tolower its density, is impregnated with 5 kinds of silica sol of Table 1above, respectively, so that adhered quantity of silica solid isapproximately 64 wt % of the weight of the ceramic paper, and then isdried for 20 minutes at 150° C. to solidify the silica sol. Thusobtained is an adsorbing sheet for humidity and odorous gas exchange.

FIG. 4 shows the result of measuring humidity adsorbing quantity of thissheet against time lapse. The measuring method starts with heating thissheet at 140° C. for 30 minutes to completely remove its humidity andthen adsorption is started. FIG. 3 shows a measuring device, in whichseveral adsorbing sheets AS are mounted with intervals in-between on astand DS. A fan F is operated to inhale air of constant temperature andhumidity from the constant temperature/humidity room CR and to send itinto a duct D. A movable heater box HD intervenes in the duct D to raisetemperature of air in the duct D to a certain level, the air is thenemitted through the adsorbing sheets AS. A thermometer T, a hygrometerHM and an anemometer V are installed before and behind the adsorbingsheets AS to measure each air condition. On the other hand the stand DSon which the adsorbing sheets AS are mounted is mounted directly on anelectronic balance EB to measure weight increase as the adsorbing sheetsAS adsorb humidity. First the fan F is operated to make constant airvelocity in the duct D. Then air is heated to 140° C. by applyingelectric current to the heater box HD and sent between the adsorbingsheets AS in parallel to them for 30 minutes in order to completelyremove humidity from them. Then a heater H is turned off to lower airtemperature in the duct D and the rising state of weight increase of theadsorbing sheets AS is measured approximately every 60 seconds startingat the point when the adsorbing sheets start adsorption. This iscontinued for 20 minutes.

FIG. 4 shows the plot of these values. As seen from FIG. 4, the smallerthe silica particle diameter is, the faster the adsorbing speed is.Among them, adsorbing speeds of No. 1 (40 Å) and No. 2 (70 Å) silicaparticles are the fastest and they can be used for a dehumidifyingelement or an element for total heat energy exchange. Adsorbingconditions are: Air temperature is 20° C., relative humidity is 70% andair speed at the front of the adsorbing sheets AS is 1 m/sec. In FIG. 4,the abscissa shows adsorbing time (minute) and the ordinate showshumidity quantity (g/m²) adsorbed to the sheets. In the drawing, No. 1,No. 2, No. 3, No. 4 and No. 5 are the adsorbed quantity curves of thehumidity on the adsorbing sheets AS against time lapse. In using arotary dehumidifier, on the other hand, as shown by arrows in FIG. 12,adsorption and desorption are repeated at every rotation of the rotor(approximately 6 minutes). Adsorbing time is approximately 4.5 minutesand desorbing time is approximately 1.5 minutes. Therefore,dehumidifying efficiency depends on how much humidity is adsorbed withinthis adsorbing time of 4.5 minutes. As shown in FIG. 4, the rising ofthe adsorbing speed becomes the fastest when silica particle diameter is40 Å-70 Å. For example, No. 2 adsorbs humidity of approximately 13 g/m²in 3 minutes and No. 1 adsorbs 21 g/m² in 3 minutes. The bigger theparticle diameter is, for example like 250 Å and 450 Å, the slower theadsorbing speed is. For example, No. 4 adsorbs humidity of 5 g/m² in 3minutes and No. 5 adsorbs humidity of 2.5 g/m² in the same 3 minutes.Therefore these with such lower adsorbing ability are unsuitable forusing as a dehumidifier nor a total heat energy exchanger. Thereforeparticles of diameter not larger than approximately 120 Å are the bestin ability for dehumidification and total heat energy exchange. On theother hand, an adsorbing element for a total heat energy exchanging bodyhas to efficiently exchange sensible heat and latent heat at the sametime at every rotation. The rotation speed of a total heat energyexchange element normally is as fast as 8-16 r.p.m. due to introductionof the maximum value of sensible heat exchanging efficiency, whichdemands extremely fast humidity adsorbing/desorbing speed. Therefore,desirable is No. 2 with particle diameter not larger than 70 Åpreferably. As seen from FIG. 4, shown is the characteristic that thesmaller the diameter of minute silica particles in silica sol is, thefaster the adsorbing speed of the sheet is.

EXAMPLE NO. 2

As shown in FIG. 2, nonflammable paper of 0.2 mm thickness is formedinto a single-faced corrugated sheet CR of 4.2 mm pitch and of 2.5 mmheight, which is then laminated and formed into a honeycomb block B of200 mm×200 mm×250 mm as shown in FIG. 1. No. 2 silica sol samplementioned above is impregnated in this block B and is dried at 150° C.for 20 minutes so that silica solid of approximately 25% of the weightof the block is rigidly fixed to obtain a cross-flow total heat energyexchange element No. 6. Or only a liner L is impregnated with No. 2silica sol beforehand which is rigidly fixed to the liner. This sheet Land a nonflammable paper C are combined to form a single-facedcorrugated sheet CR, which is laminated to obtain a cross-flow totalheat energy exchange element No. 6A.

FIGS. 5 and 6 show total heat energy, sensible heat and latent heatexchange efficiencies of the cross-flow total heat energy exchangeelement No. 6 mentioned above, a cross-flow total heat energy exchangeelement No. 7 to which prior lithium chloride of approximately 4% isimpregnated, and an element No. 8 which is prepared by impregnatinglithium chloride of approximately 4% in the total heat energy exchangeelement No. 6 mentioned above. FIG. 5 shows total heat energy exchangeefficiencies in summer conditions, i.e., outer air temperature is 35°C., its relative humidity is 40%, return air temperature is 27° C., itsrelative humidity is 60% and air velocities of both airs are 0.5-2m/sec. FIG. 6 shows total heat energy exchange efficiencies in winterconditions, i.e., outer air temperature is 7° C., its relative humidityis 70%, return air temperature is 20° C., its relative humidity is 47%and air velocities of both airs are 0.5-2 m/sec. As seen from FIG. 5,when air velocity V (air velocity m/sec. right before flowing into theelement in FIG. 1) is 2 m/sec., sensible heat exchange efficiency is by12% higher than that of the prior total heat energy exchange element No.7 which is impregnated with lithium chloride, and latent heat exchangeefficiency is by approximately 11% higher than that of the prior totalheat energy exchange element which is impregnated with lithium chloride.Total heat energy exchange efficiency of the element No. 8 of thepresent invention, too, is by approximately 13% higher than prior ones.

TABLE 2 No.8 No.6 No.7 No2. sol Winter Air Velocity No.2 sol LiCl andLiCl Conditions (m/sec.) impregnated impregnated impregnated SensibleHeat 2 77 78 66 Exchange 1 86 88 81 Efficiency 0.5 91 91 88 Latent Heat2 37 39 32 Exchange 1 58 62 45 Efficiency 0.5 72 81 56 Total Heat 2 7568 58 Energy Exchange 1 77 80 68 Efficiency 0.5 85 89 70

In summer conditions, too, total heat energy exchange efficiency is byapproximately 17% higher.

EXAMPLE NO. 3

A paper of 0.2 mm thick mainly consisting of glass fiber (alsocontaining binders, synthetic fiber, etc.) is formed into a single-facedcorrugated sheet of 4.2 mm pitch P and 2.2 mm height H as shown in FIG.7. It is rolled and laminated, being adhered at the same time, aroundthe core material S as shown in FIG. 8 to obtain a cylindrical honeycombrotor R. This honeycomb rotor R is impregnated with No. 2 silica solsample of Table 1 mentioned above and is dried at 100° C. for 30 minutesso that silica solid of 20% of the weight of the honeycomb rotor R isrigidly fixed to obtain a total heat energy exchange rotor R₁.

FIG. 9 shows total heat energy exchange efficiency of the total heatenergy exchange rotor R₁ mentioned above. FIG. 9 shows sensible heat,latent heat and total heat energy exchange efficiencies in winterconditions, i.e., outer air OA temperature is 7° C., its relativehumidity is 70%, return air RA temperature is 20° C., its relativehumidity is 45% and air velocities of the both air are 1-2.5 m/sec.

As seen in FIG. 9, the latent heat, sensible heat and total heat energyefficiencies of the total heat energy exchange rotor R₁ of the presentinvention mentioned above, which is prepared by impregnating No. 2silica gel in glass fiber sheet paper, which is rigidly fixed, arebetter than these of the total heat energy exchange rotor R₂ which hasbeen used and which is prepared by rigidly fixing approximately 20 g/m²of silica particles sold on the market of approximately 50-150 micronsize on both sides of an aluminum sheet of approximately 30 micronthickness. That is, in the case of prior rotor R₂, values of sensibleheat, latent heat and total heat energy exchange efficiencies aredifferent at velocities of 1 m/sec. and 2.2 m/sec., respectively, andits total heat energy exchange efficiency is lower by approximately 10%than that of the rotor R₁ of the present invention. As seen in FIG. 9,in the case of the total heat energy exchange rotor R₁, values ofsensible heat, latent heat and total heat energy exchange efficienciesshow almost the same characteristic throughout region of air velocity of1-2.5 m/sec. This is because the diameter of No. 2 silica gel particlesis approximately 70 Å and that of prior silica gel particles rigidlyadhered to an aluminum sheet is 50-150 microns. As No. 2 silica gelparticles are much smaller than prior silica gel, which makes itssurface area extremely large and its humidity adsorbing speed extremelyfast, as shown in FIG. 2, the value of its latent heat exchangeefficiency is high, almost corresponding to the value of its sensibleheat exchange efficiency, and its total heat energy exchange efficiencyshows the same characteristic.

EXAMPLE NO. 4

A paper of 0.2 mm thick, consisting of ceramic fiber, glass fiber and asmall amount of cellulose fiber, is formed into a single-facedcorrugated sheet of 3.4 mm pitch P and 1.8 mm height H (FIG. 10). Thisis rolled and laminated around a core material S as shown in FIG. 11 toobtain a honeycomb formed body RD. This honeycomb formed body RD isimpregnated with No. 2 silica sol (70 Å diameter of particles in sol)shown in Table 1 and is dried to obtain a dehumidifying honeycomb rotorRD₁. In this case the silica gel content is 60% of the weight of RD₁. Inanother method fine zeolite powder (particle diameter not larger than 7microns) of 20% of the weight of No. 2 silica sol shown in Table 1 isdispersed in No. 2 silica sol. The honeycomb formed body RD mentionedabove is impregnated with this dispersion and is dried to obtain adehumidifying rotor RD₂. In this case, silica gel and zeolite contentsare approximately 30% of the weight of RD₂, respectively. The rotorwidth of R₁ and RD₂ is 200 mm.

Tested were these four dehumidifying rotors RD₁, RD₂ and RO (Example 6)and a prior dehumidifying rotor RDL impregnated with 8 wt % of lithiumchloride (200 mm width) (FIG. 11) using the same device and under thesame conditions to compare their dehumidifying efficiencies. In thedehumidifier shown in FIG. 12, four rotors are installed respectively,area ratio of the dehumidifying zone 18 and the reactivating zone 19 ismade 3:1, air velocity of the process air TA and the reactivation air HAare set at 2 m/sec., respectively, temperature of process inlet air TAis set at 25° C. and temperature of reactivation inlet air HA is set at140° C. Dehumidifying performance of each dehumidifier using 4 kinds ofrotors is shown in FIG. 13. In the drawing the abscissa shows absolutehumidity (g/kg) of the process inlet air TA and the ordinate showsabsolute humidity (g/kg) of the process outlet air that passed throughrotors RD₁, RD₂, RO and RDL, respectively. As seen in FIG. 13, whenabsolute humidity of the process inlet air TA is 10 g/kg, dry air isread by the ordinate 3.2 g/kg for RDL, 2.2 g/kg for RD₁ and 1.0 g/kg forRD₂ as is read by point at 10 g/kg of the abscissa in FIG. 13. Thereforeit can be seen that the dehumidifying performance of the RD₁ rotor ofthe present invention using minute No. 2 silica gel particles is higherthan that of the prior RDL rotor which is impregnated with lithiumchloride of 8% of the rotor weight by approximately(3.2−2.2)/3.2×100=31% and also that the dehumidifying performance of theRD₂ rotor, for which minute zeolite particles are mixed into No. 2silica sol, than that of the RD₁ rotor by (2.2−1.0)/2.2×100=54%. Thecurve RA shows dried air DA temperature.

EXAMPLE NO. 5

Glass fiber paper of 0.2 mm thickness is prepared by adding organicbinder, paper strength reinforcing agent and so on to glass fiber. InNo. 2 silica sol mentioned above, minute particles of Diaion SK 1B Natype (called SK 1B hereinafter) sold by Mitsubishi Kasei KabushikiKaisha of 20% of the silica sol weight are dispersed as moistureadsorbing agent. The paper mentioned above is impregnated with thisdispersion, and is dried to rigidly fix minute silica particles ofapproximately 20% of the weight of the paper and minute SK 1B particlesof approximately 20% of the weight of the paper, thus obtaining ahumidity and odorous gas exchange sheet. SK 1B mentioned above is, asshown in FIG. 20 16, strong acid cation exchange resin sodium type(neutral) having sodium sulfonate radical (—SO₃Na) as ionization radicalchemically combined to benzene ring of synthetic resin which is formedby three-dimensional copolymerization of styrene and divinylbenzene.

Here minute silica particles act as moisture adsorbing agent and at thesame time as a binder that combines minute particles of SK 1B, which ismoisture adsorbing agent, to inside of and on the surface of the sheet.Thus obtained is a sheet with multiplied moisture adsorbing effect.

EXAMPLE NO. 6

A 0.2 mm thick paper made by mixing a small amount of pulp and glassfiber with ceramic fiber is formed into a single-faced corrugated sheetof 3.4 mm pitch and 1.8 mm height, which is rolled and laminated arounda core material S as shown in FIG. 11 to obtain a honeycomb rotor. InNo. 2 silica sol mentioned above, minute particles of SK 1B ofMitsubishi Kasei of 21% of the silica sol weight is dispersed. Thehoneycomb rotor mentioned above is impregnated with this dispersion andis dried to obtain a honeycomb dehumidifying rotor RO. The content ofNo. 2 silica gel and that of minute SK 1B particles are 20% of theweight of the dehumidifying rotor, respectively. The performance of thisrotor RO is not so good as that of a rotor using silica sol and zeolite,but is better than that of a prior rotor using lithium chloride.Therefore it is good enough to be used as a honeycomb dehumidifier.

As shown in FIG. 14, the total heat energy exchange rotor R₁ describedin Example 3 (FIG. 8) is installed rotatably in a casing 11, to whichequipped are an outer air OA duct 12, a supply air SA duct 13, a returnair RA duct 14 and an exhaust air EA duct 15. And the rotor R₁ isrotated to perform total heat energy exchange between the outer air OAand the return air RA. For a rotor with a matrix of nonflammable paper(0.25 mm thick), its rotation speed is approximately 8-10 r.p.m. and fora rotor with a matrix of an aluminum sheet (0.1 mm thick), it isapproximately 14-16 r.p.m. Air velocity is 1-2.7 m/sec. In the drawing,16 is a seal.

When each of honeycomb dehumidifying rotors RD₁, RD₂, RDL and RO is usedseparately, each of rotors RD₁, RD₂, RDL and RO is installed rotatablyin the casing 11 as shown in FIG. 12. A dehumidifying zone 18 and areactivation zone 19 are separated by a separator 17, and the rotor isrotated by a geared motor 20, a pulley 21, a tension pulley 22 and adrive belt 23 at 10-25 r.p.h. to pass the process air TA to bedehumidified through the dehumidifying zone 18 at 1-3 m/sec. to obtaindehumidified air DA and the reactivation air HA through the reactivationzone 19 in the opposite direction at the same speed of 1-3 m/sec. todesorb/reactivate the reactivation part by hot air of 80°-150° C. In thedrawing, 24 is a seal and 25 is a reactivation air heater.

In the present invention, a sheet or a honeycomb laminate is impregnatedor coated with silica sol which contains minute silica particles withnumerous stable silanol radicals on the surface and, having particlediameter not larger than 120 Å, with strong binding ability amongthemselves and with other materials. It is then dried to gelatinize andthen rigidly fixed. Therefore each minute silica particle strongly bindsto the honeycomb laminate and at the same time numerous minute silicaparticles bind with one another, thus forming numerous micropores ofseveral Å - tens Å pores diameter and being fixed inside the sheet andon the surface of the sheet. In the present invention, a sheet or ahoneycomb laminate is impregnated or coated with silica sol whichcontains minute silica particles of diameter smaller than 120 Å of theamount less than 30% of the weight of silica sol as solid content, andwhich also contains stable silanol radicals and a small amount of alkalimetal Na₂O of 0.1-1.0 wt % of silica sol. It is then dried to gelatinizein the honeycomb laminate which is then rigidly fixed. In the process ofgelatinizing, numerous minute silica particles bind with one another toform numerous micropores of several Å - tens Å pore diameter, bindinginto the material of the honeycomb laminate.

In this process, silanol radicals are fixed on the surface of themicropores mentioned above and they, together with micropores, displaystrong adsorbing performance of water molecules. The existing of smallamount of alkali metal ion also contributes to moisture adsorbingability by their property as acceptor of H₂O molecules. It has acharacteristic that the smaller the diameter of silica particles, i.e.,in silica sol is, the stronger the binding power among particles is, andwhen the amount of silica particles contained and dispersed in silicasol increases, sol is solidified in a shorter time. For example, if No.2 silica particle in Table 1 is 70 Å in diameter, silica sol solidifiesin a short time when the silica particle content in the silica sol ismore than 30%. If No. 1 silica particle in Table 1 is 40 Å in diameter,the sol is unstable and solidifies when the content of silica particlesis more than 15%. The silica sol cannot be used.

As is seen from curves No. 1 and No. 2 in FIG. 4, the smaller thediameter of silica particles in used silica sol is, the faster thehumidity adsorbing speed of resulting silica gel tends to be. On thecontrary, as is seen from curves No. 3, No. 4 and No. 5, the larger thediameter of silica particles is, the slower the humidity adsorbing speedtends to be. In the cross-flow type total heat energy exchange element(FIG. 1) shown in Example 2, humidity exchange between the outer air OAand the return air RA moves from the higher side of water vapor partialpressure between the outer air OA and the return air RA to the lowerside. When the outer air (OA) has relative humidity of 70% and thetemperature of 32° C., and the return air (RA) has relative humidity of50% and the temperature of 25° C., the higher humidity in the air OA isfirst adsorbed on micropores, silanol radicals and sodium ion (calledmicropores etc. hereinafter) of the liner L and, gives adsorption heatto the adsorbing sheet L simultaneously, moves instantaneously to theair RA through channels of numerous micropores formed by minute silicaparticles in the adsorbing sheet L. The adsorbed water then evaporates,taking away evaporation heat and gives humidity to the low humidity airRA, thus performing latent heat exchange. In other words, it isconsidered that humidity in the air OA is adsorbed by the adsorbingsheet L with strong moisture adsorbing performance to generate heat andthat the humidity and the adsorption heat simultaneously move to the airRA. That is, the larger the silica particle diameter in silica sol is,the larger the micropore diameter formed is, making adsorbing speedslower as mentioned above and therefore decreasing humidity transferfrom the air OA to the air RA to result in the decrease of the so-calledlatent heat exchange efficiency.

When silica sol is dried, silica particles in the sol aggregate intochains and then becomes three-dimensional gel networks.

Therefore, an initial particle size in silica sol controls microporesize in gel networks. That is, the larger the silica particle diameterin silica sol is, the larger the micropore diameter formed in gels is.

FIG. 15 shows the influence of the quantity of sodium ions in silica solto the adsorbing quantity. The diameter of silica particle in eachsilica sol is approximately 100 Å. It has been made clear by experimentsthat the more the quantity of Na₂O in each silica sol is, the faster theadsorbing speed is and the more the adsorbing quantity per unit hour is.The range of the content of this Na₂O is preferably 0.01-1.0%.

In the silica gel obtained from the silica sol used in the presentinvention, the smaller a minute silica particle in the silica sol is,the stronger its moisture adsorbing ability and binding ability of thesilica gel are. When other adsorbents such as zeolite, minute silica gelparticles, minute alumina gel particles, minute particles of organichigh-polymer electrolyte, etc., are mixed into silica sol, which isimpregnated in a sheet and which is rigidly fixed, the silica gel worksas a strong binder, and the adsorbents mixed and silica gel itself workas adsorbents at the same time. Thus an effective adsorbing body can beobtained.

Hereinbefore, the adsorption of humidity has been explained, but theadsorber of the present invention can be also used for the adsorption ofpolar compounds and other odorous gases such as ammonia and etherscontained in low humidity air.

As mentioned above, the present invention is to obtain a humidityexchanging body by preparing silica sol which contains as solid contentnot more than 30% of silica particles of diameter not larger than 120 Åwith many stable silanol radicals on the surface and also a littlealkali metal ion such as 0.01-1.0% of Na₂O by impregnating the silicasol or by coating it on a sheet or a laminate having numerous smallchannels, and by drying it to solid that is rigidly fixed. Therefore itsmanufacturing process is extremely simple and the humidity exchangingbody can be manufactured inexpensively and, what is more, it remarkablyimproves a total heat energy exchange efficiency or a dehumidifyingefficiency compared with prior ones.

What is claimed is:
 1. An adsorbing body for humidity and odorous gasexchange which is made by preparing silica sol which contains as solidcontent not more than 30% of minute silica particles of diameter notlarger than approximately 120 Å which have a plurality of stable silanolradicals on the surface and which have extremely strong binding abilitywith one another and strong bonding strength with other materials, byimpregnating said silica sol in or by coating it on a sheet or alaminate having numerous small channels, and by drying them togelatinize said sol that is then rigidly fixed on said sheet orlaminate.
 2. An adsorbing body for humidity and odorous gas exchangewhich is made by mixing/dispersing inorganic and/or organic humidityadsorbing or adsorbing agent into the silica sol according to claim 1,by impregnating the dispersion or by coating it on a sheet or a laminatehaving numerous small channels, and by drying it to gelatinize said solthat is then rigidly fixed.
 3. An adsorbing body for humidity andodorous gas exchange according to claim 2, in which the inorganichumidity adsorbing agent is zeolite.
 4. An adsorbing body for humidityand odorous gas exchange according to claim 2, in which the organichumidity adsorbing agent is hydrophilic organic high-polymerelectrolyte.
 5. An adsorbing body for humidity and odorous gas exchangeaccording to claim 2, in which the inorganic humidity adsorbing agent isselected from the group consisting of lithium salts, magnesium salts andcalcium salts.
 6. An adsorbing body for humidity and odorous gasexchange which is made by impregnating a salt selected from the groupconsisting of lithium salts, magnesium salts and calcium salts in asheet or a laminate which is then rigidly fixed, before or after themanufacture of the adsorbing body for humidity and odorous gas exchangeaccording to claim
 1. 7. A method for producing an adsorbing body forhumidity and odorous gas exchange comprising steps of preparing silicasol which contains as solid content not more than 30% of minute silicaparticles of diameter not larger than approximately 120 Å which have aplurality of stable silanol radicals on the surface and which haveextremely strong binding ability with one another and strong bondingstrength with other materials, impregnating said silica sol in or bycoating it on a sheet or a laminate having numerous small channels, anddrying them to gelatinize said sol that is then rigidly fixed on saidsheet or laminate.
 8. An adsorbing body for humidity and odorous gasexchange which is made by mixing an organic cation exchange resin in abinder; coating the cation exchange resin on a laminate having numeroussmall channels or on a sheet; and drying the coated sheet or thelaminate to gelatinize the cation exchange resin and binder coatedthereon.
 9. An adsorbing body according to claim 8, wherein the cationexchange resin is a strong acid cation exchange resin.
 10. An adsorbingbody according to claim 8, wherein the cation exchange resin has astructure with a cation exchange radical chemically bonded to a benzenering.
 11. An adsorbing body according to claim 10, wherein the cationexchange resin is a sodium sulfonate radical.
 12. An adsorbing bodyaccording to claim 8, wherein the cation exchange resin is a sodiumcation exchange resin.
 13. An adsorbing body for humidity and odorousgas exchange which is made by mixing an organic cation exchange resin ina binder; impregnating the cation exchange resin and binder in alaminate having numerous small channels or in a sheet; and drying theimpregnated sheet or laminate to gelatinize the cation exchange resinand binder impregnated therein.
 14. An adsorbing body according to claim13, wherein the cation exchange resin is a strong acid cation exchangeresin.
 15. An adsorbing body according to claim 13, wherein the cationexchange resin has a structure with a cation exchange radical chemicallybonded to a benzene ring.
 16. An adsorbing body according to claim 15,wherein the cation exchange resin is a sodium sulfonate radical.
 17. Anadsorbing body according to claim 13, wherein the cation exchange resinis a sodium cation exchange resin.
 18. An adsorbing body for humidityand odorous gas exchange which is made by mixing an organic cationexchange resin in a binder; coating the cation exchange resin on alaminate having numerous small channels; and drying the coated laminatesheet to gelatinize the cation exchange resin and binder coated thereon.19. An adsorbing body according to claim 18, wherein the cation exchangeresin is a strong acid cation exchange resin.
 20. An adsorbing bodyaccording to claim 18, wherein the cation exchange resin has a structurewith the cation exchange radical chemically bonded to a benzene ring.21. An adsorbing body according to claim 20, wherein the cation exchangeresin is a sodium sulfonate radical.
 22. An adsorbing body according toclaim 18, wherein the cation exchange resin is a sodium cation exchangeresin.
 23. An adsorbing body for humidity and odorous gas exchange whichis made by mixing an organic cation exchange resin in a binder;impregnating the cation exchange resin and binder in laminate havingnumerous small channels; and drying the impregnated laminate togelatinize the cation exchange resin and binder impregnated therein. 24.An adsorbing body according to claim 23, wherein the cation exchangeresin is a strong acid cation exchange resin.
 25. An adsorbing bodyaccording to claim 23, wherein the cation exchange resin has a structurewith the cation exchange radical chemically bonded to a benzene ring.26. An adsorbing body according to claim 25, wherein the cation exchangeresin is a sodium sulfonate radical.
 27. An adsorbing body according toclaim 23, wherein the cation exchange resin is a sodium cation exchangeresin.